Electric switch



A. McDANNOLD.

ELECTRIC SWITCH. APPLICATION FILED Mn. 15, 1920. RENEWED APR. 29, 192|. 1,391,782.

Patented Sept. 27,

clear, and exact description,

any reason there is camp srA'rEs PAT E T omes.

Amxmnm McDANNOLD, or summons, 21.0mm.

mncrnrc vswrren.

To all whom it'may concern:

Be it known that I, Anaxarnmn MCDAN- NOLD, a citizen of the United States, residin at Hallandale, in the county of Broward an State of Florida, have invented certain new and useful Improvements in Electric Switches, of which the following is a full, reference being had to the accompanying drawings, -formingra part hereof. a

he present invention is directed to improvements in. automatic switches for the spark-plug circuits of internal combustion engines as'applied to self-propelled vehicles generally, but tractors more'particu'larly, the object of the invention bein to stop the engine ormotor under conditions when for dangerof the tractor rearing and turning over about the axis of the rear wheels. It is a plow is attached to a tractor and the plow- .share encounters a stump or other obstructractor to wind mg arrested under stoppage of the veh clrcuit tion which suddenly arrests the travel of the vehicle, of the forward the continued 0 ration drlvi'nggear will cause the b0 of the or rear about t e axis rotation of the latter bethe circumstances by the icle. In this rearing movement of the vehicle the driver often loses his head so that he fails either to stop the 'motor or unclutch, the running gear therefrom at the critical moment and-before tllieglehicle overturns. The result is that t e 9f the rear wheels,

of him. To avoid the purpose ofv the the motor being stoped by theautomatic opening of the circuit eading from the battery to the timer and spark plugs, this automatic" breaking of the bein accomplished by especial construction 0 switch to be now described in detail in connection with the accompanying drawings in which- 7 4 .igure 1 represents a sideelevation' of a tractor showing my invention applied thereto; Fig. 2 is an enlarged side e the improved switch 1n normal position; Fig. 3 .1s a vertical cross-section on the line 3-3 of Fi 2; Fig. 4 is a vertical longitudinal sect1onal detail on the line 4-4 of Fig. 3; and Fig. 5 is a diagram showing the conventional wiring system in this class of vehicles.

Referring to the drawings, A, represents well known that where Specification of Letters Patent. Application meg mm 15, mo, sci-mm.

war is often injured or killed by'the' I machine rolling on top H such consequences is I present improvement,

wheels leaving as this falls within the any agriplow encounter an obstruction such as a 7 Patented Sept. 27, 1921. 886,019. idenewed April 29, 1921. Serial Re. 485,499.

stump or rock, bringing the machine suddenly to a stop; and since under the circumstances the rear wheelsof the tractor can not turn, the entire machine starts to revolve about. the axis of said wheels, the front the ground and the entire tractor rearing so as'to assume an incline as indicated by the dotted line a: in Fig. 1.

f the rearing continues the machine will simply overturn and may do serious injury tothe driver unless he has presence of mindto stop the engine. By my 1m rovement this is brought about automatical y.

of the tractor is" provided with from the center of-which, drical bol to rotateflthe s'leeve3 of a yoke or strap-'4 secured about the walls-of a hollow cylinder or tubular container 5, the sleeve being ro- The body a plate 1 projects a cylinvvidedwith an insulating bushing 6 termimating in flanges a which likewise insulate the band 4 from the plate 1 and from the nut n carried by the threaded end of the bolt. No claim is made for the insulationpurview of the skilled mechanic. The tube 5 1s disposed symmetri cally about the axis of the spindle 2, and since the bushing 6 is loose on the spindle it leaves the tube free to oscillate .in a vertical plane about the axis. of the spindle."

t or spindle2'about which is free The tube is'closed at the ends and contains l a body of fluent material 7 which may be mercury or itse uivalent (as for example steel balls or the ike). When the mercu is at one end of the of the tube is caused to rest on an adjustable screw ring 8 carried by an angle bracket- 9; and when the mercury is causedto run ovation of 8 to the opposite end of the tube it oscillates the latter until it is arrested b th bearing 8 carried by the'angle racket .9 at the opposite end of the plate 1, the bearings 8, being so set that when the tube enga either one of them the tube will be slightly inclined, the d on the adjustment imparted to said screws.

Leading fromthe sleeve 3 toward and of .the machineis an arm 10 dis sed parallel to the axis of the tube 5, an is rigidlyconnected to the tube by a tube the weighted end egree of inclination depending the front which is strut 11 termlnating in arms 12 which partly:

breaks the circuit which through the arm minal having leading therefrom a wire w which is connected by a screw t to the sleeve 3 (Fig. 4)

the current being conducted 10 to the wipers 13 between which it is received when'the tube 5 tilts forward (Figs. 1, 2,) said wipers forming the terminals of a conducting bracket 14 secured to but insulated from the plate 1.

A binding post 15 onthe-brac ket 14 secures the adjacentend of a wire 'w' leadin to the timer T, a suitable hand switch g being placed inthe path of said wire. From the timer T lead the wires w to the coil box C, whence lead the wires 40'' to the spark plugs m, the grounding of the current being shown by the dotted line in Fig. 5. The

. wiring is herein shown more or less conventionally, being well understood in the art and requiring no further descri ti'on.

The operat1on is obvious from igs. 1 and 2, but briefly put is as follows: When the tractor travels .on a level or on a grade insuiflcient to shift the mercury 7 from the front end of the tubular container 5 to the rear end, the front weighted end of the tube 5 keeps the switch 10 in contact with the wipers 13 and the current continues to flow to the spark plugs and keeps the engine runthe mercury the tube oscillates to the dotted position in ning, The moment however that the tractor begins to rear and assumes an angle or tilt (see line m Fig. 1) sufficient to spill or shift 7 to the rear end of the tube,

Fig. 1, throwing the switch 10 out of engagement with the wipers 13 and breaking position of the the circuit. This of course stops the engine and the tractor comes .to a stop and settles 1 down to rest on all four wheels. Thereupon the tube 5 is set by hand back to its original position, when again the circuit is closed and the machine may resume its work. The screws 8, 8, may f course be adjusted to any desired degree so as to impart any desired tilt or inclination to the tube 5. Any suitable fluent material may be confined in the tube. Mercury is perhaps the most sensitive. Balls however might well answer the purpose. The tube 5 is provided with a screw-plug d uponthe removal of which the mercury (or its eguivalent) may be poured into the tube. ny other arrangement for introducing the mercury into the tube may be substituted for that here shown.

Having described my invention what I claim is-- An electric switch comprising a tube hinged at an intermediate point about an .axis exterior to the tube to oscillate in a vertical plane, a longitudinally disposed insulated switch arm projecting from sald axis parallel to the tube and participating in the oscillations of the tube, fluent contents in the tube gravitating toward one end of the tube and keeping the same weighted at said end, an adjustable bearing against which the weighted end of the tube may rest, and a second adjustable bearing for engaging the opposite end of the tube with a tilting of the tube in the opposite direction due to the shifting of the fluent mass toward said end with a change in the angular tube.

In testimony whereof I afiix my signature,

in presence of two witnesses.

ALEXANDER M DANNOLD.

Witnesses: I

MILDRED RoMrH, E. Humans. 

